<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .mingren {         /* 声明样式 */
            color: red;  
        }
        .zuozhu {
            color: chartreuse;
        }
    </style>
</head>
<body>
    <div class="mingren">鸣人</div>  
    <!-- 引用样式 class 单词 类的意思 -->
    <div class="zuozhu">佐助</div>
</body>
</html>